A crucial evolutionary change in vertebrate history was the Palaeozoic (Devonian 419–359 million years ago) water-to-land transition, allowed by key morphological and physiological modifications including the acquisition of lungs. Nonetheless, the origin and early evolution of vertebrate lungs remain highly controversial, particularly whether the ancestral state was paired or unpaired. Due to the rarity of fossil soft tissue preservation, lung evolution can only be traced based on the extant phylogenetic bracket. Here we investigate, for the first time, lung morphology in extensive developmental series of key living lunged osteichthyans using synchrotron x-ray microtomography and histology. Our results shed light on the primitive state of vertebrate lungs as unpaired, evolving to be truly paired in the lineage towards the tetrapods. The water-to-land transition confronted profound physiological challenges and paired lungs were decisive for increasing the surface area and the pulmonary compliance and volume, especially during the air-breathing on land. All life on Earth started out under water. However, around 400 million years ago some vertebrates, such as fish, started developing limbs and other characteristics that allowed them to explore life on land. One of the most pivotal features to evolve was the lungs, which gave vertebrates the ability to breathe above water.Most land-living vertebrates, including humans, have two lungs which sit on either side of their chest. The lungs extract oxygen from the atmosphere and transfer it to the bloodstream in exchange for carbon dioxide which then gets exhaled out in to the atmosphere. How this important organ first evolved is a hotly debated topic. This is largely because lung tissue does not preserve well in fossils, making it difficult to trace how the lungs of vertebrates changed over the course of evolution.. This included four species of lunged bony fish which breathe air at the water surface, and a four-legged salamander that lives on land.To overcome this barrier, Cupello et al. compared the lungs of living species which are crucial to understand the early stages of the water-to-land transitionCupello et al. used a range of techniques to examine how the lungs of the bony fish and salamander changed shape during development. The results suggested that the lungs of vertebrates started out as a single organ, which became truly paired later in evolution once vertebrates started developing limbs. This anatomical shift increased the surface area available for exchanging oxygen and carbon dioxide so that vertebrates could breathe more easily on land.These findings provide new insights in to how the lung evolved into the paired structure found in most vertebrates alive today. It likely that this transition allowed vertebrates to fully adapt to breathing above water, which may explain why this event only happened once over the course of evolution. Lungs, the most important organ of the pulmonary complex, are rarely preserved in fossils, hindering direct evidence of how the earliest air-breathing vertebrates breathed air. Indeed, among fossil taxa, the presence of lungs has only been confirmed in coelacanths , a salamBothriolepis canadensis as a lung , assumes that the lung evolved through a modification of the pharyngeal pouch , as the Polypterus senegalus the glottis only opens to the right sac and the left sac is connected to the right sac by a separate opening , the lung anlage develops as a ventral unpaired and tubular depression of the respiratory pharynx (the posterior portion of the pharynx), surrounded by undifferentiated mesenchymal cells . Only atenegalus , and froenegalus . The rigenegalus .P. senegalus lung is internally smooth and lacks alveolation at all the examined developmental stages, except for in the 45 mm TL juvenile, in which the most anterior projection of the lung, anterior to the connection with the pneumatic duct, is slightly compartmentalized. This evidence based on the first developmental stages of P. senegalus  lung prove that the lung bud initially develops as an unpaired anlage in this taxon . is taxon . The lefis taxon  and 2.L. chalumnae, have been extensively documented , display a similar morphology, and surprisingly, left and right tubes do not arise simultaneously. Only the right sac is connected to the pharynx by a long pneumatic duct . The lefal tract , just afforsteri . There aforsteri . Our resIn early larvae with 35.5 mm TL and 42.8 mm TL, paired lungs are collapsed in its middle and posterior portion . The intS. salamandra, lungs are truly paired since both left and right lungs arise simultaneously and symmetrically and are directly connected to the trachea. Throughout the ontogeny, S. salamandra lungs have a ventral origin, and makes a partial dorsal turn-up in its posterior portion, remaining parallel to the dorsal wall of the upper gastrointestinal tract. Due to the rarity of soft tissue preservation in the fossil record, only one species of salamandrid, Phosphotriton sigei presents its lung preserved (In postmetamorphic juveniles (of 81.85 mm TL), paired lungs are already functional, not collapsed, and the main organ for oxygen-uptake . From threserved . This lureserved , such asTraditionally, vertebrate lungs are defined as ventral paired organs derived from the ventral portion of the posterior pharynx or post-pharyngeal foregut . HoweverP. senegalus and the lungfish L. paradoxa possess secondary multilobed structure from the larval stage onward since the lung is derived from a unilateral connection to the foregut  and all living sarcopterygian fishes have a clearly unpaired lung in early developmental stages  that can foregut . The pres paired , althougThe most parsimonious scenario inferred from our data mapped on the phylogenetic framework  is that From this evolutionary point of view, our results lead to a new definition of the vertebrate lung: either an unpaired or paired respiratory organ developing ventrally from the foregut. Vestigial forms secondarily released from the respiratory function should be also designated as lungs (e.g. the lung of coelacanths). Some criteria previously used for discriminating lungs from gas bladders are no longer supported, including: paired/unpaired organization, position ventral to the alimentary tract , as wellAccording to morphological evidence presented here, bifurcation morphogenesis into true paired lungs was not developed yet in osteichthyan fish ancestors. Based on the extant phylogenetic bracket, we infer that the bilaterally paired nature of the lung evolved only in the lineage towards fossil and extant tetrapods, as a synapomorphy of this clade  and 7. TP. senegalus specimens were originally obtained for the study on the molecular developmental in polypterids . The developmental series comprises fourteen specimens. Sizes are: an early embryo of 13.5 mm TL (IMU-RU-SI-0013); 11 larvae of 16 mm TL (IMU-RU-SI-0017), 17 mm TL (IMU-RU-SI-0019 and IMU-RU-SI-0022), 17.5 mm TL (IMU-RU-SI-0037), 19 mm TL (IMU-RU-SI-0038), 20.5 mm TL (IMU-RU-SI-0039), 24 mm TL (IMU-RU-SI-0040), 25.5 mm TL (IMU-RU-SI-0041), 26.5 mm TL (IMU-RU-SI-0042), 30 mm TL (IMU-RU-SI-0043), and 50 mm TL (IMU-RU-SI-0045); a juvenile of 70 mm TL (IMU-RU-SI-0048); and an adult specimen of 200 mm TL (KPM-NI 11384). For the developmental identification  we follow Specimens of S. salamandra specimens were obtained on loan at the amphibian collection of the Muséum national d’Histoire naturelle . The three developmental stages (as described at the MNHN collection) are: two early larvae MNHN 1978.636 (1) of 35.5 mm TL and MNHN 1978.636 (2) of 42.8 mm TL; larva MNHN 1985.9039 of 49.6 mm; larva in metamorphosis MNHN 1978.542 of 54.44 mm TL; small juvenile MNHN 1988.7177 of 50 mm TL; juvenile MNHN 1962.1004 of 81.85 mm TL.Six Polypterus senegalus; PSS, Polypterus senegalus sections; KPM-NI, Kanagawa Prefectural Museum Natural History, Odawara, Japan; MNHN, Muséum national d’Histoire naturelle, Paris, France; UERJ-PN, Universidade do Estado do Rio de Janeiro, Peixes Neotropicais.Institutional abbreviations: IMU-RU-SI, Iwate Medical University, Ryozi Ura Collection, Japan; PS, Due to the extremely small size of the embryos and larvae, and to the weak density difference between soft tissues of the abdominal cavity, propagation phase-contrast microtomography was the unique way to study their anatomy and histology at micrometer scale. Phase-contrast microtomography being only achieved at synchrotron sources, we accessed the anatomy of these rare and tiny samples at the Synchrotron SOLEIL and Synchrotron SPring-8. The high brightness of the synchrotrons was essential for our material and enabled the collection high resolution scans in short timescales.P. senegalus, L. paradoxa, and S. salamandra were imaged at the PSICHÉ beamline of the SOLEIL Synchrotron  while N. forsteri specimens were scanned at SPring-8 Synchrotron. The specimens were scanned isolated in a plastic tube filled with Phosphate-buffered saline (PBS) for P. senegalus and N. forsteri, ethanol for L. paradoxa, and formaldehyde for S. salamandra. They were immobilized in vertical position using gauze pads, and/or sank inside the tip of a plastic pipette in the case of tiny individuals, in order to benefit as much possible from the available field of view and thus achieve the highest possible resolution.Specimens of 2 (5× magnification) resulting in a projected pixel size of 1.3 μm, and a propagation distance of 148 mm. (2) Larger individuals were scanned using a field of view of ~12.6 × 3.3 mm2 (1× magnification) resulting in a projected pixel size of 6.17 μm, and a propagation distance of 500 mm. For individuals slightly wider than these field of views, the latter were extended horizontally by positioning the rotation axis off-centre and acquiring data over a 360° rotation of the sample. The volumes were reconstructed from the  combined radiographs using PyHST2 software  individual. Two distinct setups were used to accommodate the different sizes of the individuals . (1) Small individuals were scanned using a field of view of 2.6 × 2.6 mmsoftware , with a software . The hugN. forsteri (from 13.5 to 70 mm TL) were imaged at the SPring-8 Synchrotron, beamline 20B2. For specimens from 13.5 mm TL to 30 mm TL, a beam energy of 15 keV was used with a double bounce Si (111) monochromator. Data were obtained at three different resolutions, and correspondingly used three combinations of two lenses and fluorescent material, as follows, 2.75 µm/voxel; 1st-stage lens: ‘beam monitor 2’ f35 mm; 2nd-stage lens: Nikon 85 mm lens; GADOX thickness: 15 µm 4.47 µm/voxel; 1st-stage lens: ‘beam monitor 2’ f35 mm; 2nd-stage lens: Nikon 50 mm lens; GADOX thickness: 15 µm 12.56 µm/voxel; 1st-stage lens: ‘beam monitor 5’ f200 mm; 2nd-stage lens: Nikon 105 mm lens; GADOX thickness: 25 µm.Specimens of Neoceratodus (KPM-NI 11384) of 200 mm TL at the National Museum of Nature and Science  using the following scanning parameters: effective energy 189 kV, current 200 mA, voxel size 9.765 μm and 1000 views (slice width 0.1 mm).Datasets were acquired at propagation distances of 2.75 µm/voxel, 4.47 µm/voxel: 600 mm; 12.56 µm/voxel: 3 m and three different exposure times of 70 ms, 150 ms, and 200 ms per projection. Field of view were: pixel size × 2048  A total of 1800 projections were recorded per scan as the sample was rotated through 180°. A high-resolution computerized axial tomography scanning was performed for the adult specimen of Segmentation and 3D rendering were performed using the software MIMICS Innovation Suite 20.0  at the Laboratório de Ictiologia Tempo e Espaço of the Universidade do Estado do Rio de Janeiro. This study focused on five osteichthyan vertebrate species and investigated their lung morphology. The comparison of the observations suggests an origin of the lung as an unpaired organ, with the present-day paired forms in amniotes being a result of secondary modification. The sound morphological comparison presented provides valuable insight into the evolution of the lung. The work will be of interest to colleagues studying vertebrate evolution. public reviews designed to be posted alongside the preprint for the benefit of readers; ii) feedback on the manuscript for the authors, including requests for revisions, shown below. We also include an acceptance summary that explains what the editors found interesting or important about the work.Our editorial process produces two outputs: i) Decision letter after peer review:eLife. Your article has been reviewed by 3 peer reviewers, one of whom is a member of our Board of Reviewing Editors, and the evaluation has been overseen by Marianne Bronner as the Senior Editor. The following individuals involved in the review of your submission have agreed to reveal their identity: Anthony Graham (Reviewer #2); John A Long (Reviewer #3).Thank you for submitting your article "Lung evolution in vertebrates and the water-to-land transition" for consideration by The reviewers have discussed their reviews with one another, and the Reviewing Editor has drafted this to help you prepare a revised submission.Essential revisions:1) The authors are requested to mention what was reported about the placoderm lung and discuss the discrepancy raised by Reviewer #3.2) The manuscript should be checked for basic grammar, as pointed out by Reviewer #1.Reviewer #1 (Recommendations for the authors):I have several suggestions for consolidating the value of the manuscript listed below.1. The authors are suggested to be careful about the use of the word 'basal' – see this literature: https://resjournals.onlinelibrary.wiley.com/doi/10.1111/j.0307-6970.2004.00262.x2. Line 93 – Did the authors really analyze the 'primitive sequence' of morphogenesis? They analyzed the morphology of present-day animals in different lineages and should not have accessed any 'sequence'.3. Line 234 'which had evolved secondarily' – This part sounds too definitive and is recommended to indicate that it is just speculation. This suggestion applies to a similar part in Line 327/328.4. The authors are recommended to refer to the individual figures  in the Discussion.5. Line 313 – develop -> develops.6. Line 320 – clear unpaired -> clearly unpaired(?).7. Line 331 – tissue -> tissues.8. The sentence in Line 338-340 is difficult to follow and is recommended to be rewritten.9. Line 333 – revealed -> suggested.10. Line 341- The word 'useful' sounds too casual, so this part needs to be rewritten.11. Line 350 – the phrase 'developmental genetic level' sounds awkward, so this part needs to be rewritten.12. Line 357-359 – This statement is limited to modern species and ignores extinct evolutionary lineage. I suggest rewriting this sentence.13. Line 366 – 'water-to-land' with hyphens.Reviewer #2 (Recommendations for the authors):The Latimeria chalumnae data have been previously published – this should be more clearly flagged in the paper.Reviewer #3 (Recommendations for the authors):This paper by a leading team of established experts in basal osteichthyan respiratory anatomy and evolution provides significant new data on the anatomy and developmental biology and evolution of lungs in key basal, key osteichthyan fishes and a primitive tetrapod. The paper presented a sound historical background to the problem, but a few points that should be considered are not included. The 3D CT data combined with thin-section images substantiate their findings well. The work holds important implications for understanding how paired lungs first evolved in fishes and tetrapods, which has been a major evolutionary conundrum up to now. The methods and data presented are sound, and the illustrations are clear and relevant to the development of the intellectual arguments presented in the discussion. Reviewer #1 (Recommendations for the authors):I have several suggestions for consolidating the value of the manuscript listed below.1. The authors are suggested to be careful about the use of the word 'basal' – see this literature: https://resjournals.onlinelibrary.wiley.com/doi/10.1111/j.0307-6970.2004.00262.xWe have removed the unnecessary uses of the word ‘basal’ .2. Line 93 – Did the authors really analyze the 'primitive sequence' of morphogenesis? They analyzed the morphology of present-day animals in different lineages and should not have accessed any 'sequence'.We have accordingly deleted the mention to “primitive sequence” (now line 112).3. Line 234 'which had evolved secondarily' – This part sounds too definitive and is recommended to indicate that it is just speculation. This suggestion applies to a similar part in Line 327/328.We agree with the reviewer’s comment and have tempered our statements line 234 and 327/328 .4. The authors are recommended to refer to the individual figures  in the Discussion.Our Discussion section now includes several references to individual figures instead of only to Figure 7.5. Line 313 – develop -> develops.Change has been done.6. Line 320 – clear unpaired -> clearly unpaired(?).It should have indeed stated “clearly unpaired”, which we corrected accordingly.7. Line 331 – tissue -> tissues.Change has been done.8. The sentence in Line 338-340 is difficult to follow and is recommended to be rewritten.We have written this sentence as follows (now lines 420-423):"From this evolutionary point of view, our results lead to a new definition of the vertebrate lung: either an unpaired or paired respiratory organ developing ventrally from the foregut. Vestigial forms secondarily released from the respiratory function should be also designated as lungs ."9. Line 333 – revealed -> suggested.Changes have been done.10. Line 341- The word 'useful' sounds too casual, so this part needs to be rewritten.We have replaced “useful” with the more appropriate term “supported” (now line 427).11. Line 350 – the phrase 'developmental genetic level' sounds awkward, so this part needs to be rewritten.Although we don't consider the phrase 'developmental genetic level' to be strange , we have replaced “developmental genetic level” with the “a level of developmental mechanism” .12. Line 357-359 – This statement is limited to modern species and ignores extinct evolutionary lineage. I suggest rewriting this sentence.We have written this sentence as follows (now lines 444-447):“Based on the extant phylogenetic bracket, we infer that the bilaterally paired nature of the lung evolved only in the lineage towards fossil and extant tetrapods, as a synapomorphy of this clade .”13. Line 366 – 'water-to-land' with hyphens.Corrected (now line 454).Reviewer #2 (Recommendations for the authors):The Latimeria chalumnae data have been previously published – this should be more clearly flagged in the paper.We agree and have added the following sentence to make this point clearer in the text (lines 206-209 of our revised version):Latimeria chalumnae, have been extensively documented .”“The anatomy of the lung of fossil and extant coelacanths, as well as its ontogenic development in the extant


P < 0.05). The calculation results of all estimation formulas have a significant correlation with preoperative GFR. Preoperative MDRD-I, CKD-EPI SCysC, and FAS Scr-SCysC have good consistency. The CG formula has the highest precision and FAS Scr-SCysC has the highest accuracy. A total of 30 patients followed up after surgery, and postoperative rGFR correlated with CG, CKD-EPI, FAS, and BIS formulas (P < 0.05). But postoperative rGFR has no significant correlation with MDRD and Schwartz (P > 0.05). Postoperative CKD-EPI Scr-SCysC has best consistency, and FAS Scr-SCysC has the highest accuracy and precision. Our data suggest that eGFR equations evaluated by both serum creatinine (Scr) and cystatin C (SCysC) is not necessarily better than those evaluated by one of them alone. Among all enrolled equations, FAS Scr-SCysC is the best one to evaluate postoperative GFR in patients with renal tumors.To compare the applicability of 14 equations of estimating glomerular filtration rate (eGFR) before and after nephron-sparing surgery (NSS) for renal function assessment of patients with renal tumors. Preoperative and postoperative GFR is measured by emission computed tomography (ECT) with 99mTc-DTPA as an imaging agent as reference GFR (rGFR) to compare with all formulas. Spearman correlation analysis and Bland–Altman agreement analysis were used to evaluate the correlation between rGFR and eGFR1 to 14 before and after surgery. A total of 50 cases including 22 males and 28 females were included. The results of preoperative eGFR1–14 correlated with rGFR ( GFR refers to the number of milliliters of plasma that the kidneys completely filter and clear a certain metabolite in plasma within a unit time . It is aSince the Cockcroft-Gault (CG) formula was widely used in clinical practice in 1976 , 9. The A total of 50 patients with renal tumor who underwent NSS in Fujian Provincial Hospital from July 2020 to July 2021 were enrolled. All patients had no renal puncture, interventional surgery, radiotherapy, or chemotherapy, or other antitumor-related treatments before surgery. No history of CKD disease, renal trauma, and surgery. Clinical data include gender, age, height, weight, preoperative creatinine, urea, nitrogen, albumin (Alb), cystatin C, rGFR measured by ECT, and pathological diagnosis, as given in The patient's serum creatinine concentration was measured with the alkaline picric acid method using the Beckman CX3 analyzer. Serum cystatin C was measured on the Beckman UniCel DxC800 biochemical analyzer with the latex enhanced immunoturbidimetric method.99mTc-DTPA imaging determination rGFR: before the examination, the patient drinks 300–500 ml of water, empties the bladder, and takes the supine position. The probe is placed on the back waist, and the field of view includes both the kidneys and bladder. The imaging agent is injected into the vein of one side of the elbow in the form of a “bullet,” and two sets of images of blood perfusion and renal function are dynamically collected in two phases. The acquisition field includes the kidneys, ureters, and bladder. The first phase is 1 s/frame, and 60 frames are collected. The second phase is 20 s/frame, and the collection is 29 minutes. After the collection is completed, the empty syringe is collected again and counted for 6 s. Calculate the dose of drug injected into the body according to the count value of the syringe before and after. Use the ROI technology to outline the outline and background area of the kidneys. Then, use the supporting software to process the image and generate the kidney map to obtain the GFR of the kidneys.The measured height, weight, Scr, BUN, Alb, and SCysC values were, respectively, substituted into the 14 estimation equations included in this study, and eGFR1–14 were calculated, as given in Accuracy means the degree to which the measured value of the formula is consistent with rGFR, indicating the correctness of the calculation result. The greater the number of close agreement between the eGFR results and rGFR values of multiple patients calculated by each formula, the higher the precision of the results, showing the repeatability and stability of the formula.−2 and no patients had rGFR less than 30 ml/min/1.73 m−2. Of the 30 patients followed up after surgery, there were 12 males with an average of 56.1 ± 13.1 years old and 18 females with 48.8 ± 11.2 years old. The average time from surgery to reexamination of rGFR for 30 patients was 262 days. The average postoperative rGFR of 30 patients was 93.94 ± 20.26  and 93.49 ± 22.62 .A total of 50 cases including 22 males and 28 females, aged 17−80 years old, with an average of 53.8 ± 10.2 years old , 50 ± 10.5 years old . The average preoperative rGFR of 50 patients was 90.04 ± 15.42  and 91.71 ± 19.67 . Only 3 patients had rGFR less than 60 ml/min/1.73 mP < 0.05), among which eGFR1 (CG formula), eGFR6 (CKD-EPI Scr), eGFR7 (CKD-EPI SCysC), eGFR8 (CKD-EPI Scr-SCysC), eGFR9 (Schwartz Scr-SCysC), eGFR10 (FASScr), eGFR11 (2017 FAS SCysC), eGFR12 (FAS Scr-SCysC), eGFR13 (BIS-1Scr), and eGFR14 (BIS-2 Scr-SCysC) have a significant correlation(P ≤ 0.001), as given in RGFR is correlated with all preoperative GFR calculated by each formula (The mean line of eGFR2 (MDRD-I) is closest to 0, indicating that its calculation result is closest to rGFR, as shown in The closest moving average value to 0 is −0.13 (B). Only one calculated eGFR value was outside the 95% CI . The absolute minimum value of the intercept width is −0.2096 (A). The absolute value of the slope is the smallest, which is −0.0144 (L). The absolute value of the slope is the largest at −0.7026 (M).Scr), the average line is only 1.8. The eGFR2 (MDRD-I), eGFR7 (CKD-EPI SCysC), and eGFR12 (FAS Scr-SCysC) have good consistency, and only one patient's GFR is outside the 95% confidence interval (95% CI).Followed by eGFR10 (FAS Scr-SCysC) and eGFR7 (CKD-EPI SCysC) are −5.0456 and −5.4934 respectively. The minimum absolute value of the slope of eGFR12 (FAS Scr-SCysC) is −0.0144, indicating the highest accuracy. Followed by eGFR1 (CG formula) and eGFR7 (CKD-EPI SCysC), they are −0.0516 and −0.0592, respectively. Among the CKD-EPI related formulas , the cystatin C-based formula has the highest consistency than the equation based on creatinine and the combination formula. The FAS Scr-SCysC formula has the highest consistency than those based on creatinine or cystatin C alone.Among the 14 formulas, the absolute value of the intercept width of eGFR1 (CG formula) is the smallest, which is −0.2096, indicating that eGFR1 (CG formula) has highest accuracy than other formulas. Followed by eGFR12 (FAS Scr), eGFR7 (CKD-EPI SCysC), eGFR8 (CKD-EPI Scr-SCysC), eGFR10 (FAS Scr), eGFR11 (2017 FAS SCysC), eGFR12 (FAS Scr-SCysC), eGFR13 (BIS-1 Scr), and eGFR14 (BIS-2 Scr-SCysC) (P < 0.05). But rGFR has no significant correlation with eGFR2 (MDRD-I), eGFR3 (MDRD-II), eGFR4 (MDRD-C), eGFR5 (MDRD), and eGFR9 (Schwartz Scr-SCysC) (P > 0.05).The postoperative GFR of 30 patients measured in 14 formulas was analyzed by Spearman correlation with rGFR. The results are given in Scr-SCysC) is closest to 0. Then, there are eGFR14 (BIS-2 Scr-SCysC), eGFR5 (MDRD), and eGFR11 (2017 FAS SCysC), which have good consistency for arithmetic mean less than 2. The arithmetic mean of eGFR4 (MDRD-C) is 17.1, which is the largest value among the 14 formulas.Among eGFR1–14, the absolute value of the arithmetic mean of eGFR8 (CKD-EPI Scr-SCysC) are within 95% CI means it has better consistency. Except for eGFR4 (MDRD-C) and eGFR10 (FAS Scr), which have two GFR values outside the 95% CI, there is only one other formula. Among the 14 formulas, the absolute value of the slope and intercept of eGFR12 (FAS Scr-SCysC) is the smallest, indicating that its accuracy and precision are the highest. The accuracy of eGFR4 (MDRD-C), eGFR7 (CKD-EPI SCysC), eGFR10 (FAS Scr), and eGFR1 (CG formula) is higher, for the absolute value of their slopes are all less than 0.1. The absolute values of the intercepts of eGFR10 (FAS Scr) and eGFR7 (CKD-EPI SCysC) are smaller than those of other formulas, indicating that the accuracy of these two formulas is higher than others, as given in All calculated GFR values of eGFR8   to assesSCysC, and FAS Scr-SCysC are in good agreement with rGFR. Among them, the CG formula has the highest precision, and FAS Scr-SCysC has the highest accuracy. Renal tumors can occur in almost all age groups [The results of the study showed that there was a significant correlation between the GFR calculated by the 14 estimation formulas and rGFR before the surgery. Studies have shown that the combined formula of serum creatinine and cystatin C is better than using one of them alone , 24. Amoe groups . The FASe groups .P > 0.05), including MDRD-I, MDRD-II, MDRD-C, MDRD, and Schwartz Scr-SCysC. These formulas have limitations for the evaluation of renal function in patients with renal tumors after surgery. The Schwartz formula is mainly used to evaluate the renal function of children with CKD [In the results calculated after the operation, 5 formulas had no significant correlation , where QScr is the median number of Scr for healthy people of a specific age and gender [SCysC formula and the FAS Scr-SCysC formula [Scr-SCysC has higher applicability in China [Scr-SCysC formula after surgery has the highest accuracy and precision. Patients after surgery are recommended to use this equation for renal function assessment.In 2016, Pottel et al. proposed an eGFR equation based on Scr/Qd gender . In 2017in China . In thisScr formula using Scr, age, gender, and race as calculation variables [SCysC formula and the CKD-EPI Scr-SCysC formula based on standardized Scr and SCysC [Scr-SCysC formula are highly consistent, and the postoperative GFR calculated by CKD-EPI SCysC is more accurate than the other two formulas. These reflect the advantage of cystatin C in early recognition of renal function damage. CKD-EPI formula is mainly derived and established based on CKD patients as the baseline data. The applicability of the formula is different because of the significant differences in renal pathology between patients with renal cancer and CKD.In 2009, the United States Chronic Kidney Disease Epidemiology Cooperative Group proposed the CKD-EPI ariables . In 2012nd SCysC . In the nd SCysC . Our resThe BIS-1-2 formula is based on a study of elderly CKD white patients over 70 years of age . In thisScr-SCysC are not applicable in the calculation of glomerular filtration rate. Among them, CKD-EPI Scr-SCysC has good consistency in the assessment of postoperative GFR in patients with renal cancer. The FAS Scr-SCysC formula has the highest accuracy and precision. Both of these are recommended for clinical use. However, in this study, due to the small number of postoperative patients, large-scale and sample size clinical studies can still be carried out in the future to confirm it.For renal function assessment in patients with renal tumors before surgery, eGFR1–14 are all significantly correlated. Among them, the MDRD-I formula can more accurately estimate the GFR of patients. In similar formulas, there is no accurate conclusion about which is better for creatinine or cystatin. In the CKD-EPI formula, the formula of using cystatin C alone is more consistent. While in the FAS formula, the combination of the two is required to calculate GFR more accurately. After surgery, the MDRD-related formula and Schwartz


Nationwide analyses are required to optimise and tailor activities to control future COVID-19 waves of resurgence continent-wide. We compared epidemiological and clinical outcomes of the four COVID-19 waves in the Democratic Republic of Congo (DRC).This retrospective descriptive epidemiological analysis included data from the national line list of confirmed COVID-19 cases in all provinces for all waves between 9 March 2020 and 2 January 2022. Descriptive statistical measures  were compared using chi-squared or the Fisher–Irwin test.During the study period, 72,108/445,084 (16.2%) tests were positive, with 9,641/56,637 (17.0%), 16,643/66,560 (25.0%), 24,172/157,945 (15.3%), and 21,652/163,942 (13.2%) cases during the first, second, third, and fourth waves, respectively. TPR significantly decreased from 17.0% in the first wave to 13.2% in the fourth wave as did infection of frontline health workers (5.2% vs. 0.9%). CFR decreased from 5.1 to 0.9% from the first to fourth wave. No sex- or age-related differences in distributions across different waves were observed. The majority of cases were asymptomatic in the first (73.1%) and second (86.6%) waves, in contrast to that in the third (11.1%) and fourth (31.3%) waves.Despite fewer reported cases, the primary waves (first and second) of the COVID-19 pandemic in the DRC were more severe than the third and fourth waves, with each wave being associated with a new SARS-CoV-2 variant. Tailored public health and social measures, and resurgence monitoring are needed to control future waves of COVID-19. The coronavirus disease 2019 (COVID-19) is an infectious disease that is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The first cases were officially recorded on 31 December 2019 in the Chinese city Wuhan, China. The virus is spreading rapidly and outbreaks can grow exponentially . By 3 JuIn the Democratic Republic of Congo (DRC), the first COVID-19 case, involving an individual traveling from Europe was recorded on 10 March 2020. By 2 January 2022, there were 80,562 confirmed COVID-19 cases in the DRC. The DRC boosted their SARS-CoV-2 testing capacity by increasing the number of laboratories from 1 to 25 through decentralisation of coronavirus polymerase chain reaction (PCR) testing as well as using SARS-CoV-2 antigen rapid diagnostic tests (Ag-RDT). The COVID-19 Vaccines Global Access (COVAX) initiative supplied the first batch of COVID-19 vaccines to the DRC in April 2021 . HoweverCurrently, there are several official epidemiological definitions of the COVID-19 waves. One of the main characteristics of a wave is an increasing number of registered cases, followed by a clear and identifiable peak and a subsequent decline –18. HoweClimate-Data.org [This retrospective descriptive study using epidemiological data from the national line listing of COVID-19 laboratory-confirmed cases, analysed the data of cases reported in 26 provinces of the DRC that were registered between 9 March 2020 and 2 January 2022, and were distributed by epidemiological weeks (EW). The study period was stratified according to the EW of notification for each phase, to identify temporal trends in cases as well as waves of resurgence, as defined by the WHO. Additional data from laboratory and medical case management databases were analysed. Provincial databases were compiled at the national level by the National Multi-sectorial Committee of the COVID-19 Response (CMR COVID-19). Information on SARS-CoV-2 variants associated with a specific wave was obtained from DRC’s National Institute of Biomedical Research. We used the available online climate data from The study population comprised those who had positive test results for SARS-CoV-2 infection and whose records had been entered into the national line listing by wave category at the time of study completion (2 January 2022). The inclusion of cases was rationalised primarily by defining the case category of a suspected COVID-19 case, which has been defined in the DRC in two ways: (1) any person who presents with one or more sign(s) or symptom(s) of acute respiratory infection, regardless of disease severity; and (2) any person who was in close contact (high-risk contact) with a confirmed case and who did or did not have one or more signs or symptoms of COVID-19. Furthermore, testing was performed for the population groups residing and working in high-risk environments containing infection sources, including those in close contact with a confirmed positive case, healthcare employees or frontline workers, community participants, and workers in closed spaces , participants of a mass gathering, and incoming or outgoing travellers, as part of mandatory screening at all points of entry and borders.Each participant who underwent the test procedures received a special case-investigation questionnaire form to collect socio-demographic data as well as travel and clinical histories. The procedures for sample collection, packaging, and delivery to a laboratory setting followed the national COVID-19 response guidelines and protocols. At least one nasopharyngeal and oropharyngeal swab, based on synthetic fibres equipped with plastic shafts, had been obtained. COVID-19 confirmatory diagnostics included PCR as the gold standard, along with the Ag-RDT kit. The PCR specimens were triple-packed and transported in a sterile container, whilst using special viral tools and conditions for secure transportation and maintaining adequate and stable temperatures (2–4 °C). A confirmed case is any individual with a laboratory result (PCR or Ag-RDT) that confirms SARS-CoV-2 infection, regardless of overt or covert COVID-19.According to the WHO, the COVID-19 resurgence represents a visible growth in new COVID-19 cases that are registered following at least two consecutive weeks of low or no transmission, assuming optimal surveillance and testing activities . The COVx, the TPR; a, the number of confirmed COVID-19 cases during the study period; and b, the overall number of COVID-19 tests completed during the study period.In this study, the unit of analysis was the confirmed COVID-19 case reported for each wave. The description of the key characteristics for each wave included the duration of waves and transition periods, number of cases and deaths, epidemic peaks, variants, age, sex, symptomatic case status, travel history, and infection status of frontline health workers. In the DRC, the following parameters were compared between the four COVID-19 waves: case fatality rate (CFR), test positivity rate (TPR), percentage (%) of cases with travel history, and percentage (%) of infected frontline healthcare workers. The principal outcomes of this research project have been associated with CFR and TPR, which was the proportion (%) of all tests, completed that showed positive outcomes for SARS-CoV-2, as determined below:The CFR is the proportion of individuals diagnosed with COVID-19 who died during the study period. The median age was determined for confirmed cases and deaths due to COVID-19. Depending on the travel history and provenance of cases among travellers, we classified the confirmed COVID-19 cases as local or imported cases . Individuals manifesting at least one symptom were marked as symptomatic, whereas individuals without any symptoms  during tests were marked as asymptomatic. A new variant was identified in each wave. Furthermore, we compared seasonal parameters, including temperature and rainfall over time and the number of confirmed cases in the Kinshasa main hotspot.P value less than 0.05 was considered indicative of statistical importance.Statistical analysis was performed using R version 4.0.5  . Graphs Phase I: 03/09/2020–04/12/2020 (EW11/2020–EW15/2020)Phase II: 04/13/2020–08/23/2020 (EW16/2020–EW34/2020) = first wavePhase III: 08/24/2020–11/15/2020 (EW35/2020–EW46/2020)Phase IV: 11/16/2020–04/04/2021 (EW47/2020–EW13/2021) = second wavePhase V: 04/05/2021–05/16/2021 (EW14/2021–EW19/2021)Phase VI: 05/17/2021–08/15/2021(EW20/2021–EW32/2021) = third wavePhase VII: 08/16/2021–11/07/2021 (EW33/2021–EW44/2021)Phase VIII: 11/08/2021–01/02/2022 (EW45/2021–EW52/2021) = fourth waveAccording to the WHO’s definition of COVID-19 waves, from 9 March 2020 through 2 January 2022, the available EW-wise aggregated data facilitated the identification of eight phases of the epidemic, including four waves and four under-control and alert periods , 56,637 screening tests confirmed 9,641 documented cases (TPR: 17.0%), and 496 deaths were recorded  growth in the proportion of screening TPR and asymptomatic status during the four  waves , 137% (second vs. third wave), and 4% (third vs. fourth wave) increase, respectively  during the second wave in contrast to the first (73.1%), the third (11.1%), and the fourth (31.3%) waves. This decrease, from the second to the third and fourth waves, was statistically significant Table .The Kinshasa Province and the capital of DRC were consistently the most-affected provinces in the four waves in terms of the proportion of confirmed cases: 79.5%, 68.9%, 51.6%, and 52.2%, respectively Table .Table 3TThe DRC is characterised by diverse climates , which provide the country with abundant rainfall and sunshine. The difference in rainfall between the driest and wettest periods was 191 mm. The medium temperature throughout the year differed by 1.7 °C. December was identified as the month with the highest level of relative humidity (85.21%), whereas the month demonstrating the least relative humidity was August (65.26%). November had the largest number of rainy days (25.37 days), whereas July has the smallest number of rainy days (0.27 days). The lowest medium rainfall value of only 1 mm was recorded in July. November had the highest annual rainfall, with an average of 192 mm [The number of confirmed cases increased with low temperatures, with peaks occurring at periods of low temperatures and immediately after the peak rainfall periods Fig. a and b. To the best of our knowledge, this is the first study to describe and compare the epidemiological and clinical outcomes of the four waves of the COVID-19 resurgence in the DRC, including nationwide data. The word “wave” is attributed to a phenomenon characterised by drastic peaks and gradual declines. This suggests that, even in times of slowdown, there is potential for disease-related waves in the future –18, 20. The proportion of infected frontline workers significantly decreased from the first to the fourth wave. Increased availability of personal protective equipment in health facilities across the nation, increased awareness of the fatality of the disease, COVID-19 vaccination, and increasing levels of natural immunity following infection are possible reasons for this observation . This paDetailed SARS-CoV-2 whole-genome sequencing data from DRC’s National Institute of Biomedical Research, showed that subsequent waves were associated with new variants. In some cases, some variants were more virulent, such as the Delta variant during the third wave, while a variant such as the Omicron variant during the fourth wave was less virulent but with a greater transmissibility due to its ability to evade immunity—whether naturally acquired or through vaccination . The COVAn 18% increase in the number of screening tests performed between the first and the second waves was observed, representing 137% (second vs. third wave) and 4% (third vs. fourth wave) increase, respectively. Moreover, the increased number of screening tests may be related to a lower test positivity rate in the later waves. This can be attributed to the increased testing capacity in the DRC, owing to the decentralisation of COVID-19 PCR laboratories and the use of Ag RDTs –33. ThesThe proportion of individuals with positive results and asymptomatic status, though not statistically significant, was greater at diagnosis during the second wave than during the first wave. This finding is a reminder of the trend of a decreasing number of symptomatic cases during the second wave that was observed in Nigeria . A SpaniThe number of incident cases was greater during the waves of December and January compared to the waves in June, whilst the opposite was true for the number of deaths.The COVID-19 pandemic might be contrasted with the 2009 H1N1 influenza pandemic, which demonstrated two specific waves throughout a calendar year. These influenza cases are still recorded during the seasons, including in outbreak forms . The COVFrom December to March, seasonal coronaviruses demonstrate a distinctly high point. Several factors affect the seasonality of specific diseases , 42–44. The classical concept of herd immunity may not apply to COVID-19. Similar to the influenza virus, SARS-CoV-2 mutates continually into new variants that can escape immunity derived from infections and vaccines. Additionally, any level of herd protection against SARS-CoV-2 can be overcome by waning of infection- or vaccine-induced immunity. Thus, it is improbable that infection or vaccination will induce prolonged protection against SARS-CoV-2 . HoweverAt present, the analysis that we have presented is based on reported data and may represent under-reporting. However, the information collated is crucial for building mathematical models to predict future patterns. The reductions in wave duration coupled with increased intensity in the presence of a new variant, together with the noticeable socio-ecological effects that influence the timing of waves, provide valuable information that can be incorporated into mathematical models to predict future patterns, after adjusting for the severity/infectiousness of different variants.A limitation of our study was the use of the national testing line list which had some missing data, and it is possible that not all people who were tested had their data entered into the line list, and this may impact generalisability. However, the large amount of data that was analysed reduced the likelihood of bias that may arise due to missing data. Additionally, the information was primarily based on reported data, which was influenced by the testing strategies and capacities. However, detailed analysis across the African region has shown that even after correcting for under-reporting on the reporting date, the patterns/waves persisted in the reported data .This study provides a nationwide analysis of the epidemiological and clinical outcome characteristics of all four COVID-19 waves, which shows that increasing the SARS-CoV-2 testing capacity could lead to a significant decrease in the TPR and CFR. Each wave was associated with a particular SARS-CoV-2 variant and, when testing was coupled with continuous genomic surveillance, helped to keep the response system informed of the emergence or spread of any new variant of concern and its sublineages. Further analysis will help ascertain the major risk factors for SARS-CoV-2 transmission including importation and circulation of new variant of concern, morbidity including hospitalization and admission in intensive care units, and mortality in the DRC. Enhanced monitoring of COVID-19 waves of resurgence, increased testing capacity, sustained risk communication, improved clinical management capacity, genomic surveillance, and vaccination, especially of vulnerable populations, are measures that must be implemented and maintained to better control potential waves of COVID-19 resurgence in future outbreaks.


Electrochemical catalyst deposition performed directly onto the pretreated Ti-substrates bypasses unnecessary preparation and processing of catalyst support structures. A single Pt constant potential deposition (CPD), directly followed by pulsed electrodeposition (PED), created nanosized noble agglomerates. Subsequently, Ir was deposited via PED onto the Pt sub-structure to obtain a successively deposited PtIr catalyst layer. For the co-deposition of PtIr, a binary PtIr-alloy electrolyte was used applying PED. Micrographically, areal micro- and nano-scaled Pt sub-structure were observed, supplemented by homogenously distributed, nanosized Ir agglomerates for the successive PtIr deposition. In contrast, the PtIr co-deposition led to spherical, nanosized PtIr agglomerates. The electrochemical ORR and OER activity showed increased hydrogen desorption peaks for the Pt-deposited substrate, as well as broadening and flattening of the hydrogen desorption peaks for PtIr deposited substrates. The anodic kinetic parameters for the prepared electrodes were found to be higher than those of a polished Ir-disc.The present paper presents one- and two-step approaches for electrochemical Pt and Ir deposition on a porous Ti-substrate to obtain a bifunctional oxygen electrode. Surface pre-treatment of the fiber-based Ti-substrate with oxalic acid provides an alternative to plasma treatment for partially stripping TiO Radical steps need to be taken with respect to current energy pathways to meet the objectives of the Paris agreement, in particular, the reduction of greenhouse gas emissions across multiple sectors  . TherefoUnitized regenerative fuel cells (URFCs) can be operated as either fuel cells or electrolysers; they consist of one electrochemical cell equipped with bifunctional electrodes, resulting in a round-trip energy converting device ,10. The High membrane electrode assembly (MEA) costs represent a bottleneck for upscaling PEM-based hydrogen technology ,19,20,212, TinO2n−1, TiC or TiCN [The performance of URFCs is dependent on the configuration of the oxygen electrode and influenced by catalyst preparation, deposition technique and deposition order ,11. Begi or TiCN , were re or TiCN ,30,31,32 or TiCN ,10.2 nanocomposites, immobilized onto a commercial carbon support [−2 [The bifunctional catalyst layer of the oxygen electrode catalyzes the oxygen evolution reaction (OER) during WE-mode, and the oxygen reduction reaction (ORR) during FC-mode . PtIr is support . In addiport [−2 . Neverth4O7 or Ti5O9), or metal oxides, such as antimony doped tin-oxide (ATO), have been investigated to substitute carbon-based catalyst supports. Nevertheless, commercial ATO offers less specific surface area compared to Vulcan XC-72, resulting in 1.7 m2 g−1 and 205 m2 g−1, respectively [2 g−1 using a colloidal method, leading to a round-trip efficiency of 48% at low current densities for the URFC [Catalyst support materials based on carbon have also been considered, but the use of these supports is not favored at the oxygen electrode due to carbon corrosion ,10. Cerathe URFC . Anotherthe URFC . These bthe URFC . ModifieTo summarize, recent research into bifunctional electrochemical catalysts, support materials and electrode substrates utilizes complex, laboratory-scale methods of synthesis. Electrochemical catalyst deposition can be considered an easy, fast, scalable and industrial preparation process for electrode manufacturing. Moreover, electrochemical catalyst deposition, compared to the state-of-the-art applied spray-coating approach of chemically synthesized catalyst particles, offers the advantages of increased catalyst utilization, as the catalyst can be deposited as a graded catalyst layer ,43, and In the present study, the deposition of noble metal catalysts on a Ti-substrate was investigated to prepare a bifunctional catalyst layer using an electrochemical deposition method. Here, the ex-situ characterization of a Ti-based electrode with a Pt catalyst is first presented, followed by investigations regarding the bifunctional, electrochemical co- and successive deposited PtIr catalyst layer. The highly porous substrate material provides a large specific surface area and resistance to physiochemical and electrochemical corrosion. The characteristics of the material overcome some of the important challenges of an URFC. Combined with the fact that research is focusing on the investigation of ready-to-use electrodes, the results can be considered as valuable input for industrial scaled implementation. The bifunctionality of electrodes is strongly linked to factors such as particle size, distribution, and their interaction with the support material. All these aspects are thoroughly discussed in the present paper. ® ST 2 GDL-40-1.5) was chosen with a Ti-fiber diameter of 22 × 10−6 m and an approximate porosity of 70% according to the material datasheet. As the electrode substrate, a commercial Ti-based fleece material from BEKAERT, Zwevegem, Belgium, , acetone  and ethanol  for 10 min each. To enable electrical contact for the electrochemical catalyst deposition, and to provide deposition sites for Pt and Ir, stripping of the highly stable and electrical insulating TiO2 from the substrate surface was necessary. Therefore, two surface etching processes were investigated—physical etching with argon plasma was compared to wet-chemical etching with 10% w/v oxalic acid aqueous solution .Ti-substrates with a geometric area of 1 cm−1, and a chamber pressure of 60 Pa at 400 W using a PINK V15-GM device from Pink GmbH Thermosysteme, Wertheim, Germany. The wet chemical etching, adapted based on previous research on similar substrates [w/v oxalic acid aqueous solution  at 80 °C. Physical etching was performed based on previous research ,45,46 usbstrates ,48,49, wThe topography of the plasma-treated Ti-fibers . A Philips XL 30, Eindhoven, The Netherlands, was used to acquire the micrographs for the substrate analysis at 10 mm working distance and a cathode voltage of 25 kV and was equipped with an FEI energy dispersive X-ray spectroscopy (EDX) detector, Hillsboro, Oregon, United States, for investigation of the chemical composition and catalyst distribution. In addition, JEOL JSM-7500F, Tokyo, Japan, and TESCAN CLARA GMH HighVac UHR FE-REM equipment, Brno, Czech Republic, was used to acquire high resolution micrographs of the deposited catalyst structures, both equipped with an Octane Elect Plus detector from EDAX AMETEK, Mahwah, New Jersey, United States for EDX investigations.Depending on the total catalyst loading of the electrodes, atomic absorption spectroscopy (AAS), or inductive-coupled-plasma optical emission spectroscopy (ICP-OES), was performed to determine the specific noble catalyst loading. For AAS, a ContrAA800 apparatus from AnalytikJena, Jena, Germany, and for ICP-OES, Spectro Aros equipment from Spectro, Kleve, Germany, were used, respectively. The exact working parameters cannot be provided, these being confidential to MikroLab-Kolbe.−1 for 30 min. During the measurements, the cell was continuously purged with nitrogen at a flow rate of 10 mL min−1. The experiments were conducted at room temperature on substrates exposing a 1 cm2 geometrical surface area serving as the working electrode. A reversible hydrogen electrode (RHE) was used as the reference electrode and a coiled Pt wire as the counter electrode. The cyclic voltammograms were analyzed after 200 cycles to ensure the complete removal of impurities at the catalyst surface at a scan rate of 100 mV s−1, performed between 0.05 V vs. RHE and 1 V vs. RHE for the Pt deposited electrodes, and 1.4 V vs. RHE for the PtIr deposited electrodes, respectively. The kinetic parameters were calculated from the linear voltammograms attained with a scan rate of 5 mV s−1 between 0.05 V vs. RHE and 1.6 V vs. RHE.Electrochemical measurements were performed in a three-electrode cell configuration in 0.5 sulfuric acid on an IVIUM Vertex potentiostat. The electrolyte was de-aerated by nitrogen, using a flow rate of 100 mL min2 geometrical area) as reference, were analyzed for their ORR activity and are presented in Cyclic voltammograms from several electrodes manufactured under the same pre-treatment and Pt-deposition procedure and a polished, high-purity Pt-disc  was calculated by numerical integration of the hydrogen desorption peaks and divided by the specific charge of a monolayer of hydrogen adsorbed on a Pt surface, leading to the surface roughness factor (SRF). The specific charge for a smooth, polycrystalline Pt surface was set to 210 µC cm−2 and is widely used to determine the true (microscopic) surface area of Pt electrodes. The ECSA was obtained by dividing the SRF with the catalyst loading of the electrode. The specific Pt loading of the Ti-based electrodes was determined via AAS, the results being listed in To compare the electrodes with respect to electrochemical ORR activity, the electrochemical surface areas (ECSAs) were calculated . To obtageo.−2. The cyclic voltammograms also indicated a small variation in the formation of the hydrogen peaks, which may have resulted from the different Pt loadings.Although the discussed Pt_Ti/CPD_PED-electrodes were prepared under the same conditions, a variance in the characterization results can be observed. The specific Pt loadings for the electrodes deviated by a maximum of 64.7 µg cm2 formation during substrate assembly into the galvanic cell can influence the Pt deposition and, therefore, the obtained results.The divergence can be attributed to the wet-chemical pre-treatment of the Ti-substrate, which modifies the topography of the Ti-fibers selectively. This might create different specific surfaces of the Ti-substrates, resulting in different current densities  during electrochemical catalyst deposition, leading subsequently to different Pt agglomerate structures. These can affect the ORR activity in the cyclic voltammograms. In addition, TiOechem.2 g−1, so that the preparation chain can be considered as reproducible to a good approximation.Comparing the ECSA values where the SRF was normalized to the Pt loading, the variation between the electrodes was a maximum of 0.8 mechem.2 g−1 [echem.2 gPt−1 and 74.8 mechem.2 gPt−1 for ECSA values reported by Du et al. for self-synthesized 20 wt.% Pt/C and 40 wt.% Pt/C, respectively, the Pt/Ti_CPD_PED electrodes were outperformed [2 support, reaching an ECSA of 30.5 mechem.2 g−1 [The ECSA values obtained for the Pt/Ti_CPD_PED electrodes were six to ten times lower than the ECSA for state-of-the-art commercial Pt/C catalysts which range from 60 to 110 mem.2 g−1 . Furthererformed . It shouem.2 g−1 . This waem.2 g−1 . In contechem.2 g−1, 14 to 2.5 mechem.2 g−1, 17.8 to 11.4 mechem.2 g−1 and 25.1 to 14.1 mechem.2 g−1 were reported for potentiostatic, galvanostatic, cyclic and pulsed deposition methods applying different deposition parameters [echem.2 g−1, and were, therefore, to a good approximation, comparable to these values. Nevertheless, the difference in deposition parameters, electrolyte composition and deposition methods should be considered.Abraham et al. electrodeposited Pt onto a Ti-foil, applying different deposition methods. ECSAs in the range of 20 to 2.8 mrameters . The ECSOne approach to prepare a bifunctional oxygen electrode chosen was to deposit Pt and Ir separately in a two-step deposition process. More precisely, the previously discussed Ti-based electrode with single Pt catalyst was complemented with subsequent electrochemical Ir deposition. A detailed characterization of the single Ir deposition on the Ti-substrate can be found in a previous publication of our working group .2 stripping during material pre-treatment. It seems that the formed electric field lines should preferentially conduct to the Pt sub-structure rather than to the Ti-fibers because there was less distance between the sub-structure and the counter electrode of the galvanic cell in the microsize region. However, in order to validate this supposition, the electric field distribution during the catalyst deposition should be analyzed in further studies. A first insight into the two-step deposited PtIr electrodes (2-PtIr electrodes) is provided by SEM-micrographs in The SEM-micrographs presented in For quantifying the distribution of catalyst materials, an EDX mapping is presented in The element-specific micrographs show that the Ir was homogeneously distributed on top of the analyzed Pt agglomerates. Ir clusters were not detected in the analyzed areas of the electrode, the result being supported by the SEM-micrographs.To determine the catalyst loading, as well as the catalyst composition of the 2-PtIr electrode, AAS was performed for Pt determination, and ICP-OES for Ir determination, respectively. Results are listed in 2 geometrical area) as reference. Refer to The cyclic voltammogram obtained for the 2-PtIr electrode revealed higher specific current densities over the entire potential range compared to the Pt-disc, Ir-disc and single Pt electrode. In the voltage range of 0.05–0.3 V vs. RHE, the hydrogen desorption peaks were not separately formed compared to the Pt-disc reference. Instead, one hydrogen desorption peak was obtained without distinct peaks linked to specific oxide transition states. Similarly, anodic sweeps for PtIr catalysts were reported by Petrossians et al. . In the Desorp was estimated by numerical integration of the anodic hydrogen desorption peak and subsequently divided by the specific charge of a monolayer hydrogen adsorbed on a Pt or Ir surface leading to the SRF. The specific charges for smooth Ir and Pt surfaces covered with a hydrogen monolayer were 217 µC cm−2 and 210 µC cm−2, respectively. The specific charge values were rated according to the mass specific electrode loading [To characterize the ORR activity of the 2-PtIr electrode, the ECSA was calculated . QDesorp loading .The specific Pt and Ir loading of the Ti-based electrodes displayed in geo.−2. This was about two-times higher compared to the SRF value for the single Pt electrodes  was calculated by numerical integration in the potential range of 0.4–1.4 V vs. RHE, following the work of Rakousky [V of 52.7 mC cmgeo.−2 for the 2-PtIr electrode showed more promising OER activity compared to the QV of 3.8 mC cmgeo.−2 of the reference Ir-disc. No further conversion for the obtained QV was performed in the presented study due to the undefined contributions of the pseudo-capacity of the Ir surface, according to Rakousky [V values for Ir-based catalysts reported in the literature , the 2-To further characterize the OER activity of the electrode, LSV measurements a were peTo determine the MA, the current density at 1.6 V vs. RHE obtained from the LSV measurements was divided by the total catalyst loading see  of the eIn addition, the calculation of the kinetic OER parameters was performed based on the LSV measurements according to Tahir et al.  and Yan Pt + Ir−1. This can be explained by the high Pt loading of the electrode, which made only a small contribution to the OER activity [Pt + Ir−1 to 290 A gPt + Ir−1, and the results of Du et al. [Pt + Ir−1 to 200 A gPt + Ir−1. Considering the total catalyst loading, the MA for the 2-PtIr electrode was poor, resulting in 5 A gactivity . Similaractivity , higher activity  ranging u et al. , ranging−1 for the prepared 2-PtIr electrode was nearly six-times higher than the slope for the reference Ir-disc, implying a lower charge transfer factor on the catalyst surface. Further, Kong et al. reported Tafel slopes of 81.3 mV dek−1 and 71.1 mV dek−1 for chemically reduced Pt on commercial and self-synthesized IrO2 catalyst particles which were nearly six-times lower than the value reported here [The Tafel slope (b) of 428 mV dekted here . The lowted here . Additio0) of 14.1 A m−2 for the 2-PtIr electrode was five orders of magnitude higher than that for the Ir-disc reference  can be attributed to the applied method for electrochemical catalyst deposition. For the one-step deposition, only PED was applied, leading to the growth of more nuclei, while agglomerates grew less in size. In contrast, the areal, microsized sub-structure linked to the CPD method for single Pt and 2-PtIr electrodes was not observed for the one-step deposited PtIr electrodes , no distinct peaks for specific oxide transition states were recorded for the 1-PtIr electrode. Therefore, the cyclic voltammogram indicated a flat hydrogen peak in the entire hydrogen desorption region. This can be linked to the low catalyst loading and balanced PtIr ratio of 44:56 wt.%. Similar results were reported by Jung et al.  for a PtDesorp value and, therefore, to a low SRF of 0.4 cmechem.2 cmgeo.−2. Normalized to the catalyst loadings, ECSA resulted in 1.3 mechem.2 g−1. This can be attributed to the flattened hydrogen desorption peaks due to the catalyst loading and ratio. To characterize the ORR-activity, the ECSA was calculated according to the previously discussed procedure for 2-PtIr electrodes. The results are listed in echem.2 gPt−1 and 75.1 mechem.2 gPt−1 for PtIr alloy nanoparticles immobilized onto a carbon support with a Pt:Ir ratio of 20:20 wt.% and 20:40 wt.%, respectively [echem.2 g−1 to 80 mechem.2 g−1, outperformed the characterized 1-PtIr electrode in terms of ORR activity [echem.2 g−1, 6.1 mechem.2 g−1 and 4.4 mechem.2 g−1 for Pt:Ir ratios of 95:5 wt.%, 78:22 wt.% and 63:37 wt.%, respectively [echem.2 cmgeo.−2 and 1.9 cmechem.2 cmgeo.−2 were reported for the PtIr/C and PtIr/TiCN catalyst, respectively [Du et al. reported ECSAs of 85.3 mectively . These ractivity ,54. In cectively . This reectively . SRF valectively . Since tectively . To summarize, the 1-PtIr electrode was outperformed by alloyed carbon-based PtIr catalysts. These are not suitable for application as oxygen electrodes due to the carbon corrosion, although they are more electrically conductive than Ti-based substrates. Further, the carbon support enables a more homogenous distribution of the catalysts compared to a Ti-based substrate, leading to more accessible active sites and therefore increased ORR activity. To improve the ORR activity of the 1-PtIr electrode the substrate itself, or the pre-treatment, should be revised, and higher catalyst loadings may be required, since, up to now, only the modified areas of the Ti-fibers are covered with PtIr agglomerates see . V value was calculated according to the procedure described in 3.2.2 for 2-PtIr electrodes. The 1-PtIr electrode reached 14.1 mC cmgeo.−2, a three-times higher value than for the Ir reference, indicating a higher electrochemical OER activity. Compared to the QV of 7.3 mC cmgeo.−2 for commercial IrO2-TiO2 particles, characterized via glassy carbon RDE with an increased electrode loading of 100 µg cm−2, the 1-PtIr electrode showed a two-times higher value [V values of approximately 75 mC cmgeo.−2 and 90 mC cmgeo.−2 for Ir0.3Ti0.7O2 and IrO2 on Ti-foil were reported in the literature [−2 to 1.7 mg cm−2 [−2 [V compared to the single phase Ir catalysts. Based on the cyclic voltammogram from er value . In contterature ,65. On t mg cm−2  and 1 mgThe kinetic parameters for OER were determined based on the recorded LSV measurements shown in 2, though the IrO2-TiO2 catalyst showed a six times higher MA [Ir−1 or 187.4 A gPt + Ir−1, approximately one order of magnitude higher values compared to the 1-PtIr electrode. This significant difference may be linked to the different nanostructures of the PtIr catalysts. The nanosized Ir@Pt dendritic structure possibly offered more active sites for OER than the nanosized compact spherical PtIr agglomerates obtained in this study [2 catalyst synthesized via formic acid synthesis by Silva et al. [Ir−1, 20.3 A gIr−1 and 18.8 A gIr−1 for atomic Pt:Ir ratios of 1:9, 3:7 and 1:1, respectively, characterized via glassy carbon RDE at a slightly lower voltage of 1.55 V vs. RHE [Ir−1 for a Pt:Ir catalyst (molar ratio of 1:1) prepared via the chemical reduction method, calculated based on a voltage of 1.55 V vs. RHE [Ir−1, determined for the 1-PtIr electrode in the present study, is competitive and outperforms the catalysts of Silva et al. [The Ir-based MA of the 1-PtIr electrode was more than one order of magnitude lower than values reported for Ir or IrOigher MA . The 1-Pigher MA . The autis study . Furtheris study  were reca et al. . They re vs. RHE . Further vs. RHE . Therefoa et al.  and Konga et al. , althoug0 of the 1-PtIr electrode was nearly four orders of magnitude higher than for the Ir reference which may be linked to the different catalyst structures. The polished Ir reference offered nearly the geometrical surface area (1 cm2) for the electrochemical reactions, so that only the surface atoms participated in the reaction. In contrast, the 1-PtIr electrode offered a higher quantity of catalyst sites for the reaction, due to the nanosized and homogeneously distributed PtIr spherical agglomerates. The kinetic parameters determined from the LSV measurements listed in An electrochemically active Ti-based bifunctional electrode, with a possible direct in-situ deployment, was successfully developed via one- and two-step electrochemical deposition methods using Pt and Ir as catalysts. Two oxide-stripping methods for the electrode surface were investigated. The wet-chemical pre-treatment of the fiber-based Ti-substrate with oxalic acid resulted in a rougher surface topography compared to physical Ar plasma etching and was chosen as the pre-treatment method for the Ti-substrate.The highly porous, electrically conductive, and corrosion resistant Ti-substrate may be suitable to overcome current challenges of URFC electrodes, as it allowed the formation of electrochemically active nano- and microsized Pt and PtIr agglomerates. Spectroscopical mappings showed homogenously distributed noble metal catalysts performing competitively for both electrochemical reactions of interest. Further, it was observed that the Pt:Ir ratio influenced the electrochemical characterization results. Higher Pt content led to increased hydrogen desorption peaks, while higher Ir incorporation flattened and broaded the hydrogen desorption peaks in cyclic voltammograms. The normalization of the electrochemical results to the catalyst loading of the electrodes is highly important to enable comparisons to the existing literature. Higher Tafel slopes and exchange current densities for OER were determined in both approaches in comparison to the highly pure Ir-disc, which was related to the fiber structure of the Ti-substrate. The OER mass activity of the one-step deposited PtIr electrode was competitive with values reported in literature, due to the low catalyst loading and homogeneously distributed nanosized PtIr agglomerates obtained via the electrochemical deposition method. In contrast, the two-step deposited electrode showed lower mass activity for OER due to the high Pt incorporation of the electrode.−1 and an exchange current density of 14.1 A m−2; and a mass activity of 5 A gPt + Ir−1 determined at 1.6 V vs. RHE. The co-deposition of PtIr via the one-step method revealed: a Pt:Ir ratio of 44:56 wt.%; a Tafel slope of 436 mV dek−1 and an exchange current density of 1.3 A m−2; and a mass activity of 19.2 A gPt + Ir−1, 34.4 A gIr−1 determined at 1.6 V vs. RHE.In essence, the electrode developed with the two-step method where Pt and Ir were deposited consecutively showed the following: a Pt:Ir ratio of 99.77:0.23 wt.%; a Tafel slope of 428 mV dekThe results of the research suggest an industrially meaningful process route, concentrating on a ready-to-use architecture where the electrode investigations included the interaction between the catalyst and the electrode substrate.


P = 0.006; − 4.1 mmHg, P = 0.01; and − 1.5 kg, P = 0.008, respectively) and increased annual estimated glomerular filtration rate . In T2DM patients with poorly controlled BP, compared with GLP-1Ra, SGLT-2i treatment significantly improved BP management and increased eGFR.The cardiovascular and renal protective effects of sodium-glucose cotransporter 2 inhibitors (SGLT-2is) and glucagon-like peptide 1 receptor agonists (GLP-1Ras) are enhanced by low/controlled blood pressure (BP). However, the BP-lowering efficacy of SGLT-2is and GLP-1Ras have not been compared directly. We compared the rates of achieving target BP with SGLT-2i and GLP-1Ra treatments in Japanese patients with type 2 diabetes mellitus (T2DM). This retrospective study included 384 SGLT-2i- and 160 GLP-1Ra-treated patients with BP > 130/80 mmHg before treatment. Inverse probability weighting methods using propensity scores were used in this study. The integrated odds ratios (OR) for BP control rates were calculated and clinical changes were analyzed using a generalized linear model. SGLT-2i treatment resulted in significantly higher BP control rates than that in the GLP-1Ra treatment . Compared with GLP-1Ra, SGLT-2i treatment demonstrated significantly larger decreases in diastolic BP, mean arterial pressure, and body weight (− 3.8 mmHg,  Compared to placebo, treatment with dipeptidyl peptidase-4 inhibitors (DPP4is) demonstrated non-inferiority for major adverse cardiac outcomes6. However, treatment with saxagliptin was associated with an increased risk of heart failure5. In contrast, several CVOTs have demonstrated the predominance of sodium-glucose cotransporter-2 inhibitors (SGLT-2is)9 and glucagon-like peptide-1 receptor agonists (GLP-1Ras) in preventing major cardiovascular events compared to placebo13. Furthermore, in several CVOTs, SGLT-2i and GLP-1Ra treatments have been associated with superior renal outcomes14. Based on these findings, which support the cardiovascular and renal protective effects of SGLT-2i and GLP-1Ra, these two types of antidiabetics are highly recommended in guidelines16. The mechanisms underlying the cardiovascular and renal protective effects are not completely understood. It seems that not only their hypoglycemic effect but also other effects, such as lowering blood pressure (BP) and body weight (BW), and improving insulin resistance or lipid profile, are involved therein. The hypoglycemic effects of SGLT-2i are not essential for its protective effects. A DAPA-HF study investigating dapagliflozin17 and EMPEROR-reduced clinical trials investigating empagliflozin18 demonstrated their predominance in cardiovascular outcomes, whereas a DAPA-CKD trial showed their predominance in renal outcomes in patients with or without diabetes compared to placebo19.As rosiglitazone treatment is associated with increased cardiovascular risk, especially heart failure and myocardial infarction20. We observed that the BP-lowering effect correlated with the renoprotective effect of SGLT-2i24. We also performed a retrospective observational survey that included 547 GLP-1Ra-treated T2DM patients (data not published). Using these two reports, we directly compared the renal and cardioprotective effects of SGLT-2i and GLP-1Ra by propensity score (PS) matching25. This analysis demonstrated the significant predominance of SGLT-2i over GLP-1Ra on the renal composite outcome in T2DM patients, and that, in SGLT-2i-treated patients, the decrease in BP was significantly correlated with the decrease in ACR (P = 0.04)25.We previously performed a retrospective observational survey of 624 T2DM patients with chronic kidney disease (CKD) and demonstrated that SGLT-2i treatment decreased the urine albumin-to-creatinine ratio (ACR) in clinical practice19. BP-controlled patients at baseline may be managed to prevent excessive hypotension during SGLT-2i treatment. Therefore, the analysis including BP-controlled patients at baseline in the retrospective study cannot elucidate the role of the decrease in BP in renoprotective effects. For these reasons, we hypothesized that SGLT-2is are predominance for BP management in patients with hypertension and that they demonstrate better renal outcomes compared to GLP-1Ras. Furthermore, to the best of our knowledge, no study has reported the antihypertensive effect of SGLT-2is compared to GLP-1Ras, exclusively in BP-uncontrolled patients with hypertension. In the future, our study may support preferential treatment with SGLT-2is in patients with hypertension and DM.In addition to hypoglycemic effects, SGLT-2is and GLP-1Ras showed multifaceted effects, such as a decrease in BP and BW, and improvement in lipid profiles. These multifaceted effects may influence the organ-protective outcomes  of SGLT-2is and GLP-1Ras. However, the mechanism underlying these outcomes are not completely understood. To date, our retrospective observational study showed the predominance of SGLT-2is over GLP-1Ras in the renal outcome, and the importance of the decrease in BP for the improvement of renal outcome by SGLT-2is. However, our study included both BP-controlled and BP-uncontrolled patients at baseline. For example, the DAPA-CKD study showed renoprotective effects in patients regardless of baseline BPFurthermore, our previous study included both BP-controlled and BP-uncontrolled patients. We believe that the analysis of patients with uncontrolled BP at baseline can better demonstrate the causal relationship between the decrease in BP and renal effects.Using clinical databases, we posited that appropriate BP control is an important mechanism underlying the renoprotective effects of SGLT-2is and GLP-1Ras. However, a direct comparison of the BP-lowering effects of these two types of antidiabetic drugs has not been reported. Therefore, this study aimed to compare differences in BP control rates induced by SGLT-2i and GLP-1Ra treatments in Japanese patients with T2DM.1c (HbA1c), estimated glomerular filtration rate (eGFR), duration of treatment, and the use of sulfonylurea metformin, insulin, renin-angiotensin system inhibitors (RASis), β-blockers, and diuretics (loop and thiazides) .Supplementary Fig. The clinical characteristics of SGLT-2i- and GLP-1Ra-treated patients after inverse probability weighting (IPW) are shown in Tables Trimming using the PS value excluded 204 patients from the analysis . When using the other method, five weights were larger than 99 percentiles and were trimmed.P value was 0.03 using ATE weighting, 0.04 using ATT weighting, and 0.03 using stabilized ATE weighting). Figure Comparisons between the rates of achieving the target BP with SGLT-2i and GLP-1Ra treatments, based on the generalized linear model and integrated odds ratio (OR) analyses, are shown in Table The standardized differences among the clinical baseline characteristics depending on the type of weighting model employed are shown in Supplementary Fig. After examining the variations in standardized differences in the baseline clinical characteristics depending on the utilized weighting model, we adopted the ATE weighting model for further analysis, followed by trimming using a PS value, because this model showed the smallest median value of the standardized differences. The changes in the clinical characteristics after SGLT-2i treatment compared with GLP-1Ra treatment by analysis of the generalized linear model are shown in Table 26. To compare the efficacy of the two classes of drugs in lowering BP, we selected patients with poorly controlled baseline BP levels. SGLT-2i treatment showed a better BP control rate than GLP-1Ra treatment, which underlies the renoprotective effects of SGLT-2i treatment.We performed two retrospective cohort surveys to assess the effects of two new classes of antidiabetic drugs, SGLT-2i and GLP-1Ra, on renal function. In our previous analysis, we found that SGLT-2i has superior renoprotective effects compared to GLP-1Ra and that BP reduction caused by treatment with SGLT-2i contributed to this effect27. Statistical methods using PS, such as PS weighting and matching, may be useful in estimating treatment effects28. Among these, the PS-matching method reduces the effects of confounding factors by selecting only participants with close PS and has been used in some real-world studies, such as CVD-REAL (Comparative Effectiveness of Cardiovascular Outcomes in New Users of SGLT-2 Inhibitors)29, EMPRISE (Empagliflozin Comparative Effectiveness and Safety)30, and the J-CKD database31. These studies have evaluated the cardiovascular and renal outcomes of SGLT-2i treatment.Although randomized controlled studies provide high-quality evidence, retrospective cohort studies have serious limitations due to inadequate data on confounding factors. PS is the probability that a case is included in the treated group and is calculated using background characteristics that are considered confounding factors. PS methods have been used to control confounding factors in clinical studiesPS weighting is a PS-based statistical method. In this survey, we selected participants who did not achieve their target BP at baseline. Consequently, the sample size of both the treatment groups decreased. We obtained extreme PS between the two treatment groups in the present models ; therefore, PS matching may result in a substantial loss of sample size. Consequently, we selected the PS-weighting method for further analysis.Different weighting methods can be used depending on the primary treatment effect of interest . The formula for the weight calculation using PS is shown in Supplementary Fig. 32. Symmetric trimming, which excluded subjects with PS values ranging from 0.05 to 0.95, was reported by Richard33. The truncation of the weight for values > 99 percentiles was reported by Cole and Hernan34. Currently, there is no consensus on the best method for choosing the correct PS-weighting, trimming, or truncation method. Six statistical models were used in the survey.Lee et al. reported that trimming large weights could improve the performance of PS weightingTo avoid selecting models that would generate the most favorable results, we assessed the integrated OR as the primary outcome, calculated using a meta-analysis of data resulting from the six models applied. We concluded that SGLT-2i treatment offers superior control of BP in T2DM patients compared to GLP-1Ra treatment. Some concerns regarding this analysis must be mentioned. The ORs of the individual models were calculated using a generalized linear model analysis. The integrated OR was calculated by combining the above-mentioned ORs in the meta-analysis and using the weighted number of events. Therefore, the OR values, including the lower and upper 95% CIs, were not completely matched. Further analysis and discussion are warranted to determine the best method for assessing the OR and choosing the optimal PS weighting model. It may be difficult to define an appropriate method for PS weighting because the standardized differences had a large variance in each model utilized, as illustrated in Supplementary Fig. P < 0.0001)35; 36, respectively. A network meta-analysis concluded that SGLT-2i treatment was superior to GLP-1Ra treatment38. The renoprotective mechanism of SGLT-2is may be a result of multiple factors: favorable effects on vascular function by reducing intraglomerular pressure through restoration of tubuloglomerular feedback, improvement of hypoxia in the proximal kidney tubule, and metabolic effects, such as a reduction in BP or BW40. In turn, the renoprotective effects of GLP-1Ras may be a consequence of increased sodium excretion due to the inhibition of the sodium-hydrogen exchanger isoform 341 or anti-inflammatory and antioxidant effects43. In our previous studies, we found that SGLT-2i treatment was associated with a larger decrease in BP than GLP-1Ra treatment, and that this effect was strongly correlated with their renoprotective effects25. Regarding the secondary outcome, we selected the ATE weighting model associated with PS-based trimming to generate minimal standardized differences. Using this model for further analysis, we found that SGLT-2i treatment resulted in a greater decrease in BP and BW, and higher eGFR values than GLP-1Ra treatment. These results are similar to those of our previous study25. There was no significant difference in the decrease in LnACR between the two groups. However, a larger sample size may show that SGLT-2i treatment results in a greater decrease in LnACR than GLP-1Ra treatment. Accordingly, the renoprotective effect of SGLT-2i in T2DM patients with poorly controlled BP was superior to that of GLP-1Ra.A meta-analysis showed the predominance in composite renal outcome of SGLT-2i and GLP-1Ra treatment compared with placebo  to − 3.8 kg (semaglutide by weekly subcutaneous injection) compared to placebo. There seemed to be no significant differences in the decrease in BW between SGLT-2is and GLP-1Ras. However, the decrease in BW with dulaglutide; − 0.80  tended to be smaller than that of other GLP-1Ras and SGLT-2is. In this study, dulaglutide was administered to 33.1% of patients treated with GLP-1Ra, which may have influenced a significantly larger decrease in BW by SGLT2i than GLP-1Ras, that can induce proper BP management.Tsapas et al. reported on the comparative efficacy of hypoglycemic drugs on BW in patients with T2DM using network meta-analysis45. The use of GLP-1Ras, especially short-acting GLP-1Ras (exenatide and lixisenatide), has the potential to slow gastric emptying and prevent this phenomenon. The breakdown of GLP-1Ras in this study was 70 (43.8%) liraglutide, 53 (33.1%) dulaglutide, 5 (3.1%) exenatide, 2 (1.3%) lixisenatide, and 30 (18.8%) patients changed the GLP-1Ra type during the observation period. The unadjusted change in MAP after treatment was − 4.7 ± 11.4 mmHg in 123 patients treated with long-acting GLP-1Ras and − 5.2 ± 4.0 mmHg in 7 patients treated with short-acting GLP-1Ras. However, no significant difference was observed because of the small sample size. Future studies are needed to clarify the effect of hypoglycemic drug-induced postprandial hypotension on BP management.The prevalence of postprandial hypotension  is high in patients with T2DM46. Austin reported standardized differences exceeding 0.20 are expected, even when the PS-matched model is correctly specified47. The model used in the current study (ATE weighting associated with PS-based trimming) could decrease the imbalance between clinical characteristics at baseline. However, bias remains concerning the confounding factors that were not included in the study. This is a major limitation of this study.The standardized differences in clinical characteristics were below 0.20, with some exceptions, which were higher than 1.0, even in this model. In general, a standardized difference of < 0.10 is associated with a meaningful imbalance between the two groupsIn addition to the above-mentioned points, our comparative study has some limitations. Our surveys were small in size, retrospective, and observational, were not performed simultaneously, and did not have the same inclusion criteria. The subjects of the SGLT-2i survey were patients with T2DM and CKD, whereas those of the GLP-1Ra survey were only patients with T2DM, thus suggesting the possibility of selection bias. In clinical practice, combining both drugs are becoming a basic strategy for managing T2DM, and only patients with underlying contraindications to one of them receive the other. In this study, we compared patients receiving only one of these treatments. Therefore, our results are not applicable to patients treated with combination therapy. As only 265 GLP-1Ra-treated patients were included in the comparative analysis, selection bias appears to be a major issue in our survey.Furthermore, our survey included only data from subjects who received continuous treatment. No data on adverse events that emerged during treatment were collected. Adverse events and quality of life (QOL) are important outcomes of treatment. SGLT-2i drugs are administered orally, whereas GLP-1Ra drugs are administered by injection , which may have resulted in a lower QOL or adherence to GLP-1Ra treatment. These factors may have further influenced our results.1c levels, uncontrolled hypertension, and most predominantly chronic kidney disease), the rate of use of metformin, RASis, or statins could be low. These low rates may be considered as “insufficient management for high-risk patients.” This is one of the most important and serious limitations of our study; however, at the same time, these situations reflect the actual clinical situation in Japan. Nagasu et al. reported the renoprotective effect of SGLT-2i treatment using the Japan Chronic Kidney Disease Database (J-CKD-DB), a nationwide multicenter CKD registry31. In the J-CKD-DB, the rates of metformin, RASi, diuretic, and statin use in the SGLT-2i group were 56.7%, 46.2%, 10.8%, and 47.7%, respectively. These rates were not markedly different from those in our study, although the participants included in the studies and the types of medical institutions were not necessarily the same. Many reasons for the low rates of these medications are suspected, for example, fear of adverse effects, adherence of patients to treatment, risk of polypharmacy, or performance of patient-centered therapy. The conclusion may differ when more powerful concomitant medications are administered to patients at a high risk of renal events. A previous study showed that concomitant insulin treatment with SGLT-2i was significantly associated with a high risk of renal composite outcomes using the PS matching method48. The rate of sulfonylurea use in the insulin (+) group was significantly lower than that in the insulin (−) group even after PS matching . Although the use of sulfonylurea was not identified as an independent risk factor for renal composite outcomes by logistic regression analysis in our previous study of SGLT-2i20, further study is needed to reveal the relationship between the use of sulfonylurea and renal composite outcomes.Given that participants had a high cardiovascular risk . The efficacy in achieving the target BP rate and the characteristics of antidiabetic drugs should be considered to accomplish renoprotective effects in clinical practice.Taken together, our results demonstrate that in T2DM patients with poorly controlled BP, SGLT-2i treatment significantly improved BP management  and increased BW loss and eGFR compared to GLP-1Ra treatment  treated with each drug for more than one year, (b) aged over 20 years, and (c) diagnosed as having CKD, as defined by the K/DOQI clinical practice guidelines (only for SGLT-2i retrospective study)49. The following patients were excluded: (a) undergoing chronic dialysis, (b) type 1 DM, (c) severe liver dysfunction , (d) stage IV malignancy, (e) pregnancy, (f) poor adherence to each drug (suggested by irregular use), and (g) intending to opt out during the study. Applying these criteria, 34 patients from the SGLT-2i survey and 33 from the GLP-1Ra survey were excluded.This study is a subanalysis of our previous study, and the methods used in this study are described in our previous report1c (HbA1c), urinary ACR [mg/g Cr], and qualitative proteinuria. The estimated glomerular filtration rate (eGFR) was calculated using the following formula: eGFR (mL/min/1.73 m2) = 194 × age−0.287 × serum creatinine−1.094 × (0.739 for women)50. The formula reported by Sumida et al.51 was used to convert qualitative proteinuria values to albuminuria values. Documentation of patients’ medical records was extracted by medical doctors and anonymized patient forms were used.The following parameters were recorded at the time of initiation of each treatment and at the time of the survey: age, sex, BW, BP , serum creatinine level, glycated hemoglobin A52, BP at the office was measured in a quiet environment after resting for a few minutes in a seated position on a chair with the legs uncrossed. Attended or unattended was not specified. Two consecutive measurements were taken 1–2 min apart, and the average of the two measurements was defined as the BP at the office.BP measurements at the office were performed at each institution using validated cuff oscillometric devices. According to the Japanese Society of Hypertension Guidelines for the Management of Hypertension (JSH 2019) guidelinesA total of 140 patients in the SGLT-2i survey and 29 patients in the GLP-1Ra survey were excluded because of missing ACR values at any point during data collection. Patients concomitantly treated with both drugs were excluded. Thus, 541 and 265 patients were included in the SGLT-2i survey (SGLT-2i group) and GLP-1Ra survey (GLP-1Ra group), respectively. Patients with poorly controlled BP  were further selected. In total, 384 and 160 patients were included in the SGLT-2i and GLP-1Ra groups, respectively.52. The primary endpoint of this study was the achievement rate of target BP.In accordance with JSH 2019, the target BP for patients with T2DM is < 130/80 mmHg1c, SBP, DBP, eGFR, and the logarithmic value of LnACR at baseline, as well as the concomitant use of antihypertensive drugs, other glucose-lowering drugs, and statins. All of these factors are considered common confounding factors when assessing the efficacy of antihypertensive treatment.When different retrospective surveys are utilized to appropriately analyze the differences in the outcomes of the two treatments, adjustment for confounding factors is needed. PS analysis is useful for balancing the confounding factors between the two groups. The PS values for SGLT-2i-treated patients were calculated using a logistic regression model to estimate the probability of treatment efficacy when considering the following variables: age, sex, BW, HbAIn this study, the IPW method was used for comparative analysis. Several methods of weighting and trimming values can be utilized when the IPW method is applied. As no method is currently considered the best, we utilized three weighting methods depending on the primary treatment effect of interest: ATE weighting, ATT weighting, or stabilized ATE weighting. Supplementary Fig. Regarding other comparative analyses, the model leading to the smallest standardized differences between the clinical characteristics at baseline was selected, and a generalized linear model analysis was performed for the comparison between groups.t test was used to analyze differences in the clinical and laboratory pathological profiles between the two groups. The Mann–Whitney rank-sum test was used for continuous variables, and the chi-square test was used for categorical data in the cohort model before applying IPW. After applying IPW, a generalized linear model was used for the comparative analysis.An unpaired P < 0.05. All statistical analyses, except for the calculation of the integrated OR for the primary outcome, were performed using the IBM SPSS Statistics software .The results are presented as mean ± standard deviation, mean (lower and upper 95% CI), or median with interquartile range (IQR) for continuous data and as percentages for categorical data. Statistical significance was set at This retrospective study was conducted in accordance with the principles of the Declaration of Helsinki and was approved by the Special Ethics Committee of the Kanagawa Medical Association, Japan . The requirement for informed consent was waived by the special ethics committee of the Kanagawa Medical Association, Japan, owing to the retrospective and observational nature of the study.Supplementary Figures.